package two;

import java.util.Scanner;

public class test10344 {
    public static int[] array;

    public static void main(String[] args) {
        int n;
        Scanner scanner = new Scanner(System.in);
        n = scanner.nextInt();
        array = new int[n + 1];
        for (int i = 1; i <= n; i++) {
            array[i] = 0;
        }
        System.out.println(P(n));
    }

    private static int P(int n) {
        int sum = 0;
        if (array[n] != 0) {
            return array[n];
        }
        if (n == 1) {
            return 1;
        } else {
            for (int i = 1; i < n; i++) {
                sum = sum + P(i) * P(n - i);
            }
        }
        array[n] = sum;
        return sum;
    }
}
